This invention relates to the treatment of heart disease and cardiovascular disease in diabetic and non-diabetic patients. More specifically, the invention relates to a system and method for treating heart and cardiovascular diseases in diabetic and non-diabetic patients with Chronic Intermittent Intravenous Insulin Therapy.
The main cause of death for patients with diabetes mellitus is cardiovascular disease in its various forms. Existing evidence indicates that diabetic patients are particularly susceptible to heart failure, primarily in association with atherosclerosis of the coronary arteries and autonomic neuropathy. Furthermore, recent data also supports the existence of a disease entity called xe2x80x9cdiabetic cardiomyopathyxe2x80x9d which occurs in the absence of angiographic signs of coronary artery disease. There is little doubt that a metabolic component is present in various forms of cardiovascular disease in diabetic patients. Altered lipid metabolism (excessive lipolysis, increased free fatty acids (FFA) levels and enhanced FFA oxidation in the myocardium) and altered carbohydrate metabolism (impaired glucose oxidation in the myocardium through reduced rate of glucose utilization and depressed pyruvate dehydrogenase complex activity) lead to depressed myosin ATPase activity, decreased ability of the sarcoplasmic reticulum to take up calcium, and depression of other membrane enzymes such as Na+/K+-ATPase and Ca2+-ATPase (Rodrigues et al. J Mol Cell Cardiol, 1995, 27:169-79). The cardiac dysfunction (lower stroke volume, cardiac index and ejection fraction and a higher left ventricular end diastolic pressure) frequently manifested by patients with type 1 diabetes, could be explained at least partially by the metabolic abnormalities outlined above, and is likely secondary to insulin deficiency since appropriate insulin administration can restore normal patterns of cardiac metabolism (Avogaro et al, Am J Physiol 1990,258:E606-18). There is little dispute that an attempt should be made to lower elevated plasma triglyceride and FFA levels, thus decreasing the heart""s reliance on FFA and, hence, overcoming the FFA inhibition of myocardial glucose utilization. The abnormalities in left ventricular systolic function may be partially reversible with improvement of metabolic control of diabetes. Recently, the DIGAMI (Diabetes mellitus, Insulin Glucose infusion in Acute Myocardial Infarction) study indicated that diabetic patients with acute myocardial infarction had a 28% reduced mortality at 1 year when treated with an insulin-glucose infusion followed by multidose insulin, compared to conventional therapy (controls) (DIGAMI, Malmberg K. Br Med J, 1997,314:1512-15).
What is needed is a system and method that increases stroke volume, that improves cardiac index, that increases ejection fraction, and that lowers ventricular end diastolic pressure, thus improving cardiac function, as well as improving the quality of life of the patient. It is a further objective of this treatment to significantly reverse the cardiac dysfunction common to diabetic patients with heart disease, as well as heart disease in those who are not diabetic.
Accordingly, the present invention is a system and method capable of improving the dietary fuel capabilities of diabetic and metabolically impaired patients and correct an overutilization of free fatty acids associated with heart disease in diabetic and non-diabetic patients. The current invention is the treating of heart disease and cardiovascular disease using insulin pulses to a patient utilizing Chronic Intermittent Intravenous Insulin Therapy to achieve an increase dietary fuel capabilities and correct overutilization of free fatty acids associated with heart disease in both diabetic and non-diabetic patients.
Diabetic heart disease is the most common complication of diabetes, experienced by both type I and type II diabetic patients. Experts generally agree that the primary fuel for both the normal and diabetic heart is free fatty acids, a fuel that requires more oxygen on a per calorie basis than glucose as a fuel. As a consequence, the heart of both diabetic and non-diabetic individuals is particularly vulnerable to ischemia. Recent studies using noninvasive intravascular ultrasound instrumentation reveal that many, if not most, of the vessels in a diabetic individual with 1 coronary artery (by angiography) disease are significantly atherosclerotic. In these patients, a blood clot can temporarily or permanently block blood flow to a portion of the myocardium. If the involved tissue had been primarily utilizing free fatty acids for energy generation, even a slight or temporary decrease in blood flow or oxygen supply would be catastrophic. On the other hand, if that tissue had been burning glucose rather than free fatty acids, for the generation of an equivalent amount of energy, a temporary disruption of blood or oxygen supply would not be as deleterious, since that tissue""s oxygen requirements would be less. Thus, for the same amount of oxygen delivered to the myocardium, glucose utilization rather than free fatty acid utilization, would result in increased energy (ATP) generation.
One preferred embodiment of the invention is a system for heart disease and cardiovascular disease in diabetic and non-diabetic patients through an intravenous administration of a pulse of insulin comprises a means for determining a respiratory quotient of a patient, a liquid or food containing glucose, an intravenous site, and a means of delivering a pulse of insulin at a regular interval of time.
In the preferred embodiment of the treatment system, any instrument capable of measuring the respiratory quotient determines a respiratory quotient of a patient. The respiratory quotient is defined as the ratio of carbon dioxide produced to oxygen consumed by the patient. In the preferred embodiment, a liquid or food containing glucose is consumed by the patient to prevent hypoglycemia. The preferred liquid or food containing glucose is GLUCOLA, however any similar liquid or food containing glucose that will prevent hypoglycemia in the patient may be used.
The preferred means of delivering insulin is an infusion device. It is preferable that the infusion device is capable of providing pulses of insulin on a prearranged interval, so long as there is sufficient glucose in the blood to keep the patient from becoming hypoglycemic. The preferred infusion device is also capable of delivering the pulses of insulin in as short duration of time as possible, without adversely affecting the vein at the site of infusion is used. However, less accurate devices may deliver the pulses and achieve the needed infusion profile of approximately six minutes.
In the preferred embodiment, the intravenous site is a temporary or permanent IV access site located in the body, forearm or hand of the patient. The amount of insulin is tailored to achieve increased glucose utilization by the diseased myocardium. Improved physical activity, decreased angina and increased ejection fraction measure increased glucose utilization. Type 1 diabetic patients receive 20-35 milliunits of insulin per kilogram of body weight per pulse and type 2 diabetic patients receive 70-200 milliunits of insulin per kilogram of body weight per pulse. During periods of non-use, the IV site is preferably converted to a heparin or saline lock.
In one embodiment of the method of the invention, the patient is seated in a blood drawing chair and a 23 gauge needle/catheter is inserted into a hand or forearm vein to obtain vascular access. Although a 23 gauge needle catheter is preferred, any system of such access may accomplish the needed result, including indwelling catheters. After a short equilibration period, usually thirty minutes, the respiratory quotient (the ratio of carbon dioxide produced to oxygen consumed by the patient) of the patient is measured. The respiratory quotient measuring device may be any presently known model manufactured by any presently known supplier of such instruments. In the preferred embodiment, the patient is then asked to drink or eat liquid or food containing glucose usually on the order of 60 to 100 grams of glucose. In the preferred embodiment a pulse of insulin is administered intravenously on a regular interval of time, usually every six minutes, until the respiratory quotient (RQ) shows improvement, as indicated by a respiratory quotient of 0.90 or greater. In the preferred embodiment, improvement in RQ is generally achieved within one hour. In the preferred embodiment, the insulin/oral glucose phase is then followed by a rest period of usually one hour. In the preferred embodiment the entire procedure repeated until the desired effect is achieved.
The preferred method of insulin pulse delivery would be a prearranged interval, so long as there is sufficient glucose in the blood to keep the patient from becoming hypoglycemic. In order to determine the progress of the patient, it is preferable the RQ is measured every hour and blood glucose levels are checked every 30 minutes. The blood glucose level may be measured by any means which shows that the patient is not becoming hypoglycemic. In the preferred embodiment, the patient is free to move around after the initial insulin pulses have been administered. In the preferred embodiment, the intravenous site is converted to a heparin or saline lock. The patient returns to the blood drawing chair to receive their next series of insulin pulses. In the preferred embodiment, the subsequent insulin pulses must be covered by supplying glucose by mouth or other means. The total time of the preferred procedure is approximately 6-7 hours.
In the preferred embodiment, two successive days of three treatments are performed with a new patient. In the preferred embodiment, the above is then repeated once a week. For patients who need a more intensive approach, it is preferable the procedure be repeated 3 or more times, including continuously each week until the desired clinical outcome is achieved.
In the non-diabetic patient more glucose may be required than in the diabetic patient, but the other parameters would remain the same, including the need for a pulse delivery.